ORIGINAL: causeitflies
Any failure of the check valve would most likely result in a gradual leak that wouldn't cause a problem unless the gas could build up in a pocket. Now if there was a major leak, like a line coming off, then there is a VERY good chance that there would be a MAJOR fire.
the only way you'd have a 'Major Leak' with PowerMax is if the onboard tank exploded. if you hook up an onboard system as you should, you install a dump valve that you're supposed to empty the system at the end of the flying day, when you open this valve the expansion of gas from liquid to gas causes cooling of the liquid and reduces the pressure, and at times the flow out the dump valve will completely stop just like when you're out in cold weather and have to shake hell out of the PowerMax can to get enough for a start.
again, you'll never know you have a leak of any size until you try to fill the tank again and when you disconnect after filling it sprays back out on you, no in flight fire of explosion.